Modernize Nix configuration

default.nix

@@ -1,19 +1,2 @@
-{ haskellPackages ? (import <nixpkgs> {}).haskellPackages }:
-
-haskellPackages.cabal.mkDerivation (self: rec {
-  pname = "liblastfm";
-  version = "0.5.1";
-  src = builtins.filterSource (_: type: type != "unknown") ./.;
-  buildDepends = with haskellPackages; [
-    aeson cereal cryptoApi httpClient httpClientTls networkUri
-    profunctors pureMD5 semigroups text xmlConduit
-  ];
-  testDepends = with haskellPackages; buildDepends ++ [
-    hspec hspecExpectationsLens HUnit lens lensAeson xmlHtmlConduitLens
-  ];
-  meta = {
-    description = "Lastfm API interface";
-    license = self.stdenv.lib.licenses.mit;
-    platforms = self.ghc.meta.platforms;
-  };
-})
+{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc7101" }:
+nixpkgs.pkgs.haskell.packages.${compiler}.callPackage ./liblastfm.nix {}

example/recommendations.hs

@@ -31,7 +31,7 @@ main = withConnection $ \conn -> do
   mapM_ Text.putStrLn (concat r)
 
 -- Construct signed query
-query :: Connection -> Request JSON (APIKey -> SessionKey -> Sign) -> IO (Either LastfmError Value)
+query :: Connection -> Request 'JSON (APIKey -> SessionKey -> Sign) -> IO (Either LastfmError Value)
 query conn r = lastfm conn $ sign secret (r <*> ak <*> sk <* json)
  where
   ak     = apiKey "__YOUR_API_KEY__"

example/sort-friends.hs

@@ -67,7 +67,7 @@ forConcurrently = flip mapConcurrently
 pretty :: [(Text, Score)] -> IO ()
 pretty = mapM_ (\(n,s) -> Text.putStrLn $ n <> ": " <> s) . take 5 . sortBy (flip compare `on` snd)
 
-query :: Connection -> Request JSON (APIKey -> Ready) -> IO (Either LastfmError Value)
+query :: Connection -> Request 'JSON (APIKey -> Ready) -> IO (Either LastfmError Value)
 query conn r = lastfm conn (r <*> apiKey "234fc6e0f41f6ef99b7bd62ebaf8d318" <* json)
 
 target :: Text

liblastfm.nix

@@ -0,0 +1,24 @@
+{ mkDerivation, aeson, base, bytestring, cereal, containers
+, crypto-api, hspec, hspec-expectations-lens, http-client
+, http-client-tls, HUnit, lens, lens-aeson, network-uri
+, profunctors, pureMD5, semigroups, stdenv, text, xml-conduit
+, xml-html-conduit-lens
+}:
+mkDerivation {
+  pname = "liblastfm";
+  version = "0.5.1";
+  src = ./.;
+  buildDepends = [
+    aeson base bytestring cereal containers crypto-api http-client
+    http-client-tls network-uri profunctors pureMD5 semigroups text
+    xml-conduit
+  ];
+  testDepends = [
+    aeson base bytestring cereal containers crypto-api hspec
+    hspec-expectations-lens http-client http-client-tls HUnit lens
+    lens-aeson network-uri profunctors pureMD5 text xml-conduit
+    xml-html-conduit-lens
+  ];
+  description = "Lastfm API interface";
+  license = stdenv.lib.licenses.mit;
+}

shell.nix

@@ -0,0 +1,17 @@
+{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc7101" }: let
+  inherit (nixpkgs) pkgs;
+  ghc = pkgs.haskell.packages.${compiler}.ghcWithPackages( ps: with ps; [
+    hdevtools doctest
+  ]);
+  cabal-install = pkgs.haskell.packages.${compiler}.cabal-install;
+  pkg = (import ./default.nix { inherit nixpkgs compiler; });
+in
+  pkgs.stdenv.mkDerivation rec {
+    name = pkg.pname;
+    buildInputs = [ ghc cabal-install ] ++ pkg.env.buildInputs;
+    shellHook = ''
+      ${pkg.env.shellHook}
+      export IN_WHICH_NIX_SHELL=${name}
+      cabal configure --package-db=$NIX_GHC_LIBDIR/package.conf.d
+    '';
+  }

src/Network/Lastfm/Request.hs

@@ -30,15 +30,14 @@ module Network.Lastfm.Request
   , Targeted, comparison, Scrobble, LibraryAlbum, LibraryArtist
   ) where
 
-import Control.Applicative
-import Data.Int (Int64)
-import Data.Monoid ((<>), mempty)
-
+import           Control.Applicative
+import           Data.Int (Int64)
+import           Data.Monoid ((<>), mempty)
 import qualified Data.Map.Strict as M
 import           Data.Text (Text)
 import qualified Data.Text as T
 
-import Network.Lastfm.Internal
+import           Network.Lastfm.Internal
 
 
 class Argument a where
@@ -96,15 +95,15 @@ post = wrap $ \r -> r { _method = "POST" }
 --
 -- This is a little helper. It's actually enough
 -- to specialize Format manually
-json :: Request JSON a
+json :: Request 'JSON a
 json = wrap id
 {-# INLINE json #-}
 
 -- | Change API response format to XML
 --
 -- This is a little helper. It's actually enough
 -- to specialize Format manually
-xml :: Request XML a
+xml :: Request 'XML a
 xml = wrap id
 {-# INLINE xml #-}
 

src/Network/Lastfm/Response.hs

@@ -74,15 +74,15 @@ class Supported f r | f -> r, r -> f where
   parseResponseBody :: Lazy.ByteString -> Maybe r
   parseResponseEncodedError :: r -> Maybe LastfmError
 
-instance Supported JSON Value where
+instance Supported 'JSON Value where
   prepareRequest r = r { _query = M.singleton "format" "json" `M.union` _query r }
   parseResponseBody = decode
   parseResponseEncodedError = parseMaybe $ \(Object o) -> do
     code <- o .: "error"
     msg  <- o .: "message"
     return (LastfmEncodedError code msg)
 
-instance Supported XML Document where
+instance Supported 'XML Document where
   prepareRequest = id
   parseResponseBody = either (const Nothing) Just . parseLBS def
   parseResponseEncodedError doc = case fromDocument doc of

test/api/SpecHelper.hs

@@ -53,17 +53,17 @@ shouldHaveResponse q l = do
     Just _  -> return ()
     Nothing -> assertFailure (printf "Query failed on %s" (show r))
 
-shouldHaveJson :: Request JSON Ready -> Fold Value a -> Expectation
+shouldHaveJson :: Request 'JSON Ready -> Fold Value a -> Expectation
 shouldHaveJson = shouldHaveResponse
 
-shouldHaveXml :: Request XML Ready -> Fold Document a -> Expectation
+shouldHaveXml :: Request 'XML Ready -> Fold Document a -> Expectation
 shouldHaveXml = shouldHaveResponse
 
 -- | Check success stuff for POST requests
-shouldHaveJson_ :: Request JSON Ready -> Expectation
+shouldHaveJson_ :: Request 'JSON Ready -> Expectation
 shouldHaveJson_ l = shouldHaveResponse l (key "status".only "ok")
 
-shouldHaveXml_ :: Request XML Ready -> Expectation
+shouldHaveXml_ :: Request 'XML Ready -> Expectation
 shouldHaveXml_ l = shouldHaveResponse l (root.attributed (ix "status".only "ok"))
 
 -- | Make a request using public API key